Tip: Switch palace switches normally disappear if you replay the level. However, if you insert them as direct Map16 and use the hex-edit at $00EEB2 in the ROM map, you can replay the level without a problem.
This is the flying cloud from YI that contains an item. You can customize which sprite is spawned by modifying the extra property bytes. It is triggered with a shell or a stunned enemy. It comes with some pre-configured CFG files that spawn certain items.